The present invention relates to an apparatus for controlling the fuel injection timing of a fuel injection pump, and more particularly to a fuel injection timing control apparatus for controlling the fuel injection timing of a fuel injection pump, which is constructed so as to perform the adjustment of fuel injection by controlling the opening/closing of a solenoid valve located between a high pressure chamber and a lower pressure portion of the fuel injection pump.
In the prior art, there is known a fuel injection apparatus which has a solenoid valve located between a high pressure chamber and a lower pressure portion of a fuel injection pump, in which the high pressure chamber is made to communicate with the lower pressure portion or alternatively to disconnect from the lower pressure portion by means of the opening/closing operation of this solenoid valve, thereby regulating both the amount of fuel injection and the fuel injection timing. In this type of fuel injection pump, the control of the fuel injection timing (advance angle of injection) needs to be performed with the delay in the response of the solenoid valve taken into consideration. Because of this, Japanese Patent Public Disclosure No. 231150/84 discloses a device in which a target ignition timing according to the operating condition of an engine is calculated and the actual injection timing of one particular cylinder under consideration out of a plurality of cylinders of the engine is detected in order to measure the difference in time between the target ignition time and the actual ignition time, whereby the ignition timing of each cylinder is controlled so as to reduce the difference to zero.
However, in this conventional device, the sensor for detecting the actual ignition timing is mounted only on one of a plurality of cylinders of the engine, and the control of the ignition timing of the other cylinders is performed in accordance with the difference in timing between the target ignition timing and the actual ignition timing of this particular cylinder under consideration. Consequently, in such a case as when the speed of the engine has suddenly changed, it has the problem of not being able to control the fuel injection timing accurately.